Semiconductor device comprising a copper alloy as a barrier layer in a copper metallization layer
View Patent ↗By forming a tin and nickel-containing copper alloy on an exposed copper surface, which is treated to have a copper oxide thereon, a reliable and highly efficient capping layer may be provided. The tin and nickel-containing copper alloy may be formed in a gaseous ambient on the basis of tin hydride and nickel, carbon monoxide in a thermally driven reaction.
1. A method, comprising:
forming a copper-containing metal region in a first dielectric layer of a metallization layer of a semiconductor device, said copper-containing metal region having an exposed oxidized surface; and
exposing said exposed oxidized surface to a gaseous ambient comprising at least temporarily a tin hydride gas (SnH 4 ) and comprising at least temporarily a nickel and carbon monoxide containing gas for converting said oxidized surface into a tin and nickel-containing copper alloy.
2. The method of claim 1 , further comprising depositing a second dielectric layer on said first dielectric layer and said tin and nickel-containing alloy.
3. The method of claim 2 , wherein said second dielectric layer is formed in situ with said tin and nickel-containing copper alloy.
4. The method of claim 1 , further comprising treating said copper-containing metal region in an oxidizing ambient to form said exposed oxidized surface.
5. The method of claim 1 , further comprising:
forming a dielectric layer above said copper-containing metal region;
forming an opening in said dielectric layer to expose said tin and nickel-containing copper alloy;
forming a first copper oxide layer on inner walls of said opening;
converting said first copper oxide layer into a conductive barrier layer comprising a first tin and nickel-containing copper alloy by exposing said semiconductor device to a gaseous ambient to form said conductive barrier layer; and
filling said opening with a copper-containing metal.
6. The method of claim 5 , wherein said gaseous ambient comprises at least temporarily a tin hydride gas (SnH 4 ).
7. The method of claim 5 , wherein said gaseous ambient comprises at least temporarily a nickel and carbon monoxide containing gas.
8. The method of claim 5 , wherein forming said first copper oxide layer comprises depositing copper and exposing the semiconductor device to an oxidizing ambient.
9. The method of claim 5 , wherein forming said copper oxide layer comprises depositing copper in an oxidizing ambient.
10. The method of claim 5 , wherein filling said opening with a copper-containing metal comprises filling in said metal by an electrochemical process and removing excess material of said copper-containing metal and said barrier layer outside of said filled opening to form an exposed metal surface.
11. The method of claim 10 , further comprising treating said exposed metal surface to form a second copper oxide layer thereon.
12. The method of claim 11 , further comprising treating said second copper oxide layer in a gaseous ambient to form a tin and nickel-containing alloy on said second copper oxide layer.
13. The method of claim 5 , wherein said copper-containing metal is deposited on said conductive barrier layer.
14. The method of claim 5 , wherein filling said opening with a copper-containing metal comprises forming a seed layer on said barrier layer.